Curved ultrasonic surgical blade

ABSTRACT

An ultrasonic surgical device including an elongate waveguide having a longitudinal axis and a distal end, and a blade extending away from the distal end of the waveguide, the blade including a curved portion that has at least five faces extending lengthwise along at least a portion of the length of the blade. Each of the faces has a width that extends perpendicular to the longitudinal axis of the waveguide and a length that extends orthogonal to the width. Each of the faces is flat across its width and is either flat along its entire length or includes one or more curved segments along its length, with each of the curved segments of an individual face being curved in the same direction. A method of fabricating an ultrasonic surgical device is also provided.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a divisional of U.S. patent application Ser.No. 15/751,587 filed Feb. 9, 2018 (issued as U.S. Pat. No. 11,058,449 onJul. 13, 2021), which was a national stage entry under section 371 ofInternational Application No. PCT/US16/46911 filed Aug. 12, 2016, whichclaimed priority under 35 U.S.C. 119 to U.S. Provisional PatentApplication No. 62/204,079, filed on Aug. 12, 2015, entitled “CurvedUltrasonic Surgical Blade.” The entire disclosures of the foregoingapplications are incorporated by reference herein.

BACKGROUND

Ultrasonically driven surgical blades have been used for quite some timein the cutting, coagulation and/or dissection of tissue during variousmedical procedures. Compared to conventional static scalpels, forexample, ultrasonically driven blades typically require less force forcutting tissue, and can also provide coagulation of blood vessels(particularly when the device includes a clamp member associated withthe blade).

Ultrasonic surgical blades are usually provided at the end of anelongate waveguide, which in turn is operatively coupled to anultrasonic transducer. The transducer, often provided as part of, orhoused within, a handpiece, is adapted to convert electrical energy(typically supplied by an external generator) into vibrational motion,typically longitudinal vibrations, at an ultrasonic frequency. In manyinstances, the transducer includes a “Langevin stack” of piezoelectricdisks for this purpose. The standing wave produced by the transducer istransmitted from the transducer to the waveguide, and propagates thelength of the waveguide to the blade located at the distal end of thewaveguide. As a result, the blade vibrates at an ultrasonic frequency.

When the ultrasonically vibrating blade is urged against tissue, such asby manipulation of a handpiece and/or by clamping tissue between theblade and a clamp member, the mechanical vibratory energy of the bladeis transmitted to the tissue, not only cutting the tissue but alsogenerating frictional heat and causing cavitation, coaptation andcoagulation of the tissue.

In some instances, the blade is straight and, when used with alongitudinally vibrating transducer, vibrates solely in the longitudinaldirection (parallel to the longitudinal axis of the waveguide). However,it is often desirable to provide ultrasonically driven blades that arecurved in one or more directions. Curved blades provide a variety ofadvantages, including greater access to certain sites within a patientas well as improved visibility during use. While curved blades, whenoperatively connected to a longitudinally vibrating transducer (e.g.,via an elongate waveguide) will generally vibrate in at least onenon-longitudinal direction (e.g., transversely) due to the asymmetricalnature of the curved blade with respect to the longitudinal axis of thewaveguide, such non-longitudinal vibrations in the blade during use canbe advantageous. For example, some curved blades that vibrate in atleast one non-longitudinal direction may provide greater bladedisplacement, particularly at the distal end of the blade.

Curved blades, however, can be difficult to manufacture. For example,curved blades of the prior art typically have one or more faces (i.e.,surfaces) which are curved in two or more directions, thus requiring theuse of specialized equipment such as angled chamfer end mills (alsoreferred to as milling cutters), multiple types of end mills and precisedepth-of-cut (Z-axis) control of the milling machine in order to obtainprecise blade (i.e., “end effector”) geometry. While simpler, squarecross-section blades are easier to fabricate, allowing the use of lesscomplex machining processes, these blades do not provide the benefits ofa curved blade geometry.

While a variety of devices and techniques may exist for providing curvedultrasonically driven blades, it is believed that no one prior to theinventor has made or used an invention as described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming the invention, it is believed that the inventionwill be better understood from the detailed description of certainembodiments thereof when read in conjunction with the accompanyingdrawings. Unless the context indicates otherwise, like numerals are usedin the drawings to identify similar elements in the drawings. Inaddition, some of the figures may have been simplified by the omissionof certain elements in order to more clearly show other elements. Suchomissions are not necessarily indicative of the presence or absence ofparticular elements in any of the exemplary embodiments, except as maybe explicitly stated in the corresponding detailed description.

FIG. 1 depicts a partial cross-sectional view of one embodiment of anultrasonic surgical device having a curved blade.

FIG. 2 depicts one embodiment of an ultrasonic generator and attachedtransducer with which the ultrasonic surgical device of FIG. 1 can beused.

FIG. 3A depicts a schematic side view of an ultrasonic shears device.

FIG. 3B depicts a partial cross-sectional view of the ultrasonic shearsdevice of FIG. 3A.

FIG. 4A depicts a perspective view of the blade portion of theultrasonic surgical device of FIG. 1.

FIGS. 4B-4E depict side views of the blade of FIG. 4A, with eachsuccessive view rotated counter-clockwise (as viewed from the distal endof the blade) from the previous view.

FIG. 5 depicts an enlarged view similar to FIG. 4B.

FIGS. 6A-6E depict views similar to FIGS. 4A-4E of an alternativeembodiment of a blade, with each successive view rotated clockwise (asviewed from the distal end of the blade) from the previous view.

FIG. 7 depicts a perspective view of yet another embodiment of a blade.

FIGS. 8-13B depict a method of manufacturing the blade of FIG. 5.

FIG. 14 depicts a side view of another alternative embodiment of ablade.

FIG. 15 depicts a perspective view of yet another embodiment of a blade.

FIGS. 16 and 17 depict front perspective and side views of the distalportion of the ultrasonic shears device of FIGS. 3A and 3B, with FIG. 17depicting the clamp member in its fully closed position against theblade.

FIGS. 18 and 19 depict perspective, and partially cut-away perspectiveviews of another alternative blade.

FIG. 20 is a schematic illustration of a blade having an uppermostcurved face, wherein the radius of curvature of that face changescontinuously along the length of that face.

FIGS. 21-25 depict views similar to FIGS. 6B-6E of another alternativeembodiment of a blade, with each successive view rotatedcounter-clockwise (as viewed from the distal end of the blade) from theprevious view.

The drawings are intended to illustrate rather than limit the scope ofthe present invention. Embodiments of the present invention may becarried out in ways not necessarily depicted in the drawings. Thus, thedrawings are intended to merely aid in the explanation of the invention.Thus, the present invention is not limited to the precise arrangementsshown in the drawings.

DETAILED DESCRIPTION

The following detailed description describes examples of embodiments ofthe invention solely for the purpose of enabling one of ordinary skillin the relevant art to make and use the invention. As such, the detaileddescription and illustration of these embodiments are purelyillustrative in nature and are in no way intended to limit the scope ofthe invention, or its protection, in any manner. It should also beunderstood that the drawings are not to scale and in certain instancesdetails have been omitted, which are not necessary for an understandingof the present invention.

Embodiments of the present disclosure provide a curved blade for usewith an ultrasonic transducer for medical purposes. The blades describedherein have a curved portion that includes at least five faces whichextend lengthwise along at least a portion of the blade, at least one ofthose faces includes one or more curved segments such that the blade hasat least one curved surface along with a plurality of blade edgessuitable for cutting tissue. Each of the faces of the blade is flatacross its width, wherein that width extends perpendicular to theprojected longitudinal axis of the waveguide. The curved segments of anindividual face are all curved in a single direction, although thatcurvature may be positive and/or negative on a single face. The curvedblade is provided at the distal end of a waveguide, and the waveguide isadapted for operative coupling (directly or indirectly) to an ultrasonictransducer. In some instances, a clamp member is operatively locatedadjacent to the curved blade for selective engagement with a face and/oran edge of the blade so as to provide for both coagulating and cutting,thus providing a surgical forceps arrangement (also referred to asultrasonic shears). With or without an associated clamp member, thecutting blade may be used for ultrasonically cutting, coagulating and/ordissecting tissue. It will also be understood that the term “curvedsegment” encompasses a face having a single curved segment that extendsthe entire length of that face (e.g., the curved segment length is 100%of the face).

The curved blade embodiments described herein are configured so as tosimplify fabrication, while still providing a plurality of blade edgessuitable for cutting tissue. By providing a plurality of blade edges,embodiments described herein allow surgeons to employ a greater range oftechniques and effects. In addition, curved blade embodiments describedherein also allow for tissue cutting in more than one direction, oftenwithout the surgeon having to reposition the device.

FIG. 1 is a partially cross-sectional view of one embodiment of anultrasonic surgical device (10) comprising an elongate waveguide (12)and a curved blade (24). In the particular embodiment shown, ultrasonicsurgical device (10) also includes a sheath assembly comprising a hollowcylindrical sheath (60) and a sheath coupler (70) at the proximal end ofthe sheath (60). In other embodiments, the sheath assembly is omitted.

In the embodiment shown in FIG. 1, the waveguide (12) is located withinthe sheath (60) and sheath coupler (70). However, the sheath assembly isnot secured directly to the waveguide (12). Instead, and as detailedbelow, waveguide (12) is operatively attachable at its proximal end toan ultrasonic transducer, and sheath coupler (70) is secured to thetransducer housing. It will be understood, however, that waveguide (12)may be secured to the sheath assembly (i.e., to sheath (60) and/orsheath coupler (70)), such as by welding, adhesive attachment or inother ways known in the art.

The waveguide (12) includes an internally threaded connector portion(14) at its proximal end, as well as a plurality of flats (16) arrayedabout the circumference of the waveguide (12) adjacent to connectorportion (14). The flats (16) provide an integral nut on waveguide (12)for use in tightening the waveguide onto a transducer, as explainedbelow. While waveguide (12) is depicted as being of unitaryconstruction, in alternative embodiments waveguide (12) comprises two ormore portions joined to one another (e.g., by threaded attachment). Forexample, in one alternative embodiment, connector portion (14) and flats(16) comprise a unitary structure which is threadably attached at theproximal end of waveguide (12) (e.g., by use of an internally threadedbore and a mating threaded stud connecting the two portions of thewaveguide (12)). Similarly, although blade (24) is depicted as beingintegral with waveguide (12), in alternative embodiments the blade (24)is a separate structure that is attached to the distal end of waveguide(12), such as by threaded attachment.

FIG. 2 illustrates an exemplary generator (80) and ultrasonic transducer(82) with which the ultrasonic surgical device (10) may be used. It willbe understood that generator (80) and transducer (82) are merelyexemplary, as ultrasonic surgical device (10) can be used with any of avariety of generators and transducers. Transducer (82) includes ahousing (84) which is configured to facilitate grasping and manipulationof the transducer housing (84) by a medical practitioner. The proximalend of the housing (84) includes an electrical connector (e.g., a plugor a socket) for operative connection to the generator (80) via a matingconnector (81) provided at the end of a cable similarly connected to thegenerator (80). Thus, an electrical drive signal comprising analternating current of ultrasonic frequency is supplied from thegenerator (80) to the transducer (82) via the cable and connector (81).Transducer (82) converts the drive signal into a standing, ultrasonicvibrational wave in the transducer, including the distal portion (85) ofthe transducer horn (or velocity transformer, not shown) which protrudesfrom the distal end of housing (84). The transducer housing (84) alsoincludes a threaded projection (89) at its distal end, adjacent distalportion (85) of the transducer horn.

A threaded mounting stud (88) is secured to the distal portion (85) ofthe transducer horn, such as by being threadably and adhesively securedwithin a threaded bore (not shown) in distal portion (85). Thus,threaded stud (88) extends distally away from the distal end wall (86)of distal portion (85). It should also be pointed out that the distalend wall (86) of distal portion (85) of the transducer horn is locatedat an antinode of the standing vibrational wave produced by thetransducer (82). By way of example, generator (80) and transducer (82)in the depicted embodiment are configured to generate a standingvibrational wave having a frequency of about 55 kHz. However, variousother ultrasonic frequencies may be employed, such as between about 20and about 120 kHz.

Ultrasonic surgical device (10) may be operatively coupled to thetransducer (82) in a variety of ways. In the embodiment shown, connectorportion (14) at the proximal end of the waveguide (12) includes athreaded bore (17) that extends inwardly (i.e., distally) from theproximal end wall (15) of connector portion (14). Threaded bore (17) issized and configured to threadably receive mounting stud (88) oftransducer (82) therein for operatively coupling the waveguide (12) tothe transducer (82). When connector portion (14) is threaded onto themounting stud (88) of the transducer (82), the proximal end wall (15) ofconnector portion (14) is in abutment with the distal end wall (86) ofdistal portion (85) of transducer (82). When coupled in this manner, thestanding vibrational wave produced in the transducer is propagated alongthe length of the waveguide (12). Flats (16) are used to further tightenthe waveguide (12) onto the distal end of the transducer (82), and atorque wrench (not shown) may be used to ensure that the waveguide isnot over tightened.

As mentioned previously, the sheath assembly comprises cylindricalsheath (60) and sheath coupler (70), which are affixed to one another asshown. The sheath (60) may be affixed to the sheath coupler (70) in avariety of ways such as by welding, adhesive and/or swaging. In theexemplary embodiment shown in FIG. 1, a proximal portion (61) of sheath(60) is secured within a suitably configured cavity within coupler (70),adjacent the distal end of the coupler. In addition, the inner diameterof proximal portion (61) of sheath (60) is larger than the innerdiameter of the portion of sheath (60) external to the coupler (70) inorder to receive the connector portion (14) and flats (16) of waveguide(12) within proximal portion (61).

Sheath coupler (70) is generally hollow and includes a threaded cavity(72) extending inwardly away from proximal end wall (74) of the coupler(70). Once the waveguide (12) has been operatively coupled to thetransducer (82) in the manner described previously, the sheath assemblyis slid over the waveguide (12). In particular, blade (24) is insertedthrough the threaded cavity (72) followed by waveguide (12). Thereafter,sheath coupler (70) is threadably secured to the transducer housing (84)by the threaded engagement of threaded projection (89) within threadedcavity (72), with the proximal end wall (74) of the coupler (70) inabutment with the end wall (87) of transducer housing (84). Onceassembled in this manner, at least a portion of blade (24) extendsbeyond the distal end wall (62) of sheath (60), as seen in FIG. 1. Inother words, in some embodiments, a proximal portion of the blade(including proximal portions of the faces of the blade, describedfurther herein) is positioned within the sheath, while a distal portionof the blade extends beyond the distal end wall of the sheath (asdepicted in FIG. 1). Of course, it will be understood that the waveguide(12), blade (24), and/or sheath assembly can be configured such thateither more or less of the blade (24) extends beyond the distal end (62)of sheath (60) than is depicted in FIG. 1 (see, e.g., FIGS. 3A and 3B).In general, enough of blade (24) should protrude beyond the distal endof sheath (60) to provide adequate visualization, reach, andmanipulation of the blade for cutting, dissection and coagulation duringuse, while not having so much of the blade (24) exposed that there is aheightened risk of unintended contact between the blade (24) and tissue.

In the embodiment shown in FIG. 1, between about 0.5 and about 2.5 cm ofblade (24) extends beyond the distal end wall (62) of sheath (60). Inother embodiments, between about 1.0 and about 2.0 cm of blade (24)extends beyond the distal end wall (62) of sheath (60). In still furtherembodiments, about 15% to about 85% of the distal ¼ wave, or about 30%to about 70% of the distal ¼ wave of the blade (24) is exposed. Thedistal ¼ wave is the region extending between the most distalvibrational node and the distal tip (26) of the blade—i.e.,approximately the length of the blade (24) which extends fromapproximately the most distal node to the distal tip (26).

During use of the ultrasonic surgical devices and blades describedherein, various forces applied at the blade (24) will tend to causelateral deflection of the waveguide (12) within the sheath (60). Inorder to prevent contact between the inner wall of sheath (60) and blade(24) and waveguide (12), thereby limiting or preventing potential damageto the ultrasonic device (10) as well as damping of the standing wave,one or more spacers are provided between the waveguide (12) and theinterior of sheath (60) in order to maintain the waveguide (12) in thecenter of the sheath (60) (i.e., the longitudinal axis of the waveguide(12) aligned with the longitudinal axis of the sheath (60)). In theembodiment shown in FIG. 1, resilient rings (17A, 17B) are provided onthe exterior of waveguide (12), and comprise, for example, siliconerings. Since the amplitude of the longitudinal vibration of thewaveguide (12) at the driving frequency (e.g., 55 kHz) during use iszero at the nodes of the standing wave, the resilient rings (17A, 17B)are located at or near the vibrational nodes of the waveguide (12) inorder to limit damping of the standing wave. Rings (17A, 17B) also dampany vibrations having frequencies other than the drive frequency, sincethe nodes of vibrations of other frequencies will generally not coincidewith the node locations for the drive frequency.

Resilient rings (17A, 17B) can be supported and maintained in place in avariety of ways known to those skilled in the art. For example, in theembodiments shown in FIGS. 6, 7 and 14, an annular support (220, 320,420) for a resilient ring is provided on the waveguide, and theresilient ring can be, for example, insert molded over the support (220,320, 420) or secured over the annular support in other ways known tothose skilled in the art (e.g., adhesively, bonding, etc.). Annularsupports can be formed, for example, by lathe turning. As yet anotheralternative, and as seen in the embodiment of FIGS. 18 and 19, acircumferential groove (621) is provided on the waveguide (e.g., bylathe turning so as to form two adjacent rings with the groove locatedtherebetween). The resilient ring can then be maintained in positionmechanically by trapping the ring within groove (621). Similararrangements may be employed for securing additional resilient ringsabout the waveguide. In some embodiments, resilient rings (17A, 17B) areprovided at or near two or more vibrational nodes, depending in part onthe length of the waveguide.

As is known to those skilled in the art, a variety of other features maybe provided on the waveguide (12). For example, waveguide (12) shown inFIG. 1 includes a plurality of segments of varying diameter, with tapers(18A, 18B, 18C) providing a smooth transition between segments ofdifferent diameters. In the exemplary embodiment shown in FIG. 1, firstsegment (12A) is located adjacent flats (16) and has a diameter smallerthan that of the flats (16) region in order to amplify the standingvibrational wave. A first taper (18A) is located at the distal end offirst segment (12A), and provides a smooth transition from the largerdiameter of first segment (12A) to the smaller diameter of secondsegment (12B). Similarly, a second taper (18B) is located at the distalend of second segment (12B), and provides a smooth transition from thesmaller diameter of second segment (12B) to the larger diameter of thirdsegment (12C). Finally, a third taper (18C) is located at the distal endof third segment (12C) (adjacent resilient ring (17B), at themost-distal vibrational node of the waveguide), and provides a smoothtransition from the larger diameter of third segment (12C) of waveguide(12) to the smaller diameter of the blade (24). These changes indiameter serve to, among other things, adjust the amplitude and/orfrequency of the vibrational wave propagating the length of thewaveguide. It will be understood, however, that this is merely oneexemplary arrangement of the waveguide. Alternative embodiments includeany number of segments of varying diameters, depending, in part, on thedesired length of the waveguide (which will depend, for example, on theintended use of the instrument).

The ultrasonic surgical device comprising waveguide (12) and blade (24)can be made from any of a variety of materials, particularly variousmedically and surgically acceptable metals such as titanium, titaniumalloy (e.g., Ti6Al4V), aluminum, aluminum alloy, or stainless steel. Thewaveguide (12) and blade (24) shown in FIG. 1 are formed as a singleunit, fabricated from a single metal rod that has been milled so as toprovide the depicted features. Alternately, the waveguide and blade maycomprise two or more separable components of the same of differingcompositions, with the components coupled to one another by, forexample, adhesive, welding, a threaded stud, and/or other suitable waysknown to those skilled in the art. For example, waveguide (12) may beconfigured as two pieces joined together at or between flats (16) andfirst segment (12A). Similarly, blade (24) may be constructed separatelyfrom waveguide (12) and joined to the distal end of waveguide (12).

It will also be understood that the ultrasonic surgical devicecomprising waveguide (12) and blade (24) may be used without the sheathassembly simply by operatively coupling the proximal end of thewaveguide (12) (i.e., connector portion (14)) to transducer (82) (viathreaded mounting stud (89)). Sheath (60), however, not only protectsthe waveguide (12), but also prevents inadvertent contact between thewaveguide (12) and the patient, medical personnel or the surgicalenvironment. Not only will such contact damp vibration of the waveguide(12), but it can also cause injury to the patient or medical personnelsince the waveguide (12) is ultrasonically vibrating.

An alternative embodiment of an ultrasonic surgical device (110) isdepicted in FIGS. 3A and 3B, wherein the device (110) is configured asultrasonic shears (also known as a clamp coagulator or ultrasonicforceps) having a clamp member (150) pivotally supported adjacent curvedblade (124). The clamp member (150) is adapted for selective engagementwith a face or an edge of the blade (124) so as to provide for thesimultaneous cutting and coagulation of tissue urged against a face oredge of blade (124) by the clamp member (150). Blade (124) is similar toblade (24) in FIG. 1 or may be configured similar to the various othercurved blade embodiments described herein. In the embodiment shown,clamp member (150) is located and configured for selective engagementwith an upper, concavely curved face of the blade (124).

Ultrasonic surgical device (110) is, apart from the blade (124) and theclamp member (150), similar to the apparatus shown and described in U.S.Pat. No. 5,322,055 (which is incorporated by reference herein). Like theprevious embodiment, the curved blade (124) is provided at the distalend of an elongate waveguide (112). While waveguide (112) and blade(124) are depicted as being of unitary construction, in alternativeembodiments waveguide (112) comprises two or more portions joined to oneanother (e.g., by threaded attachment). Similarly, although blade (124)is depicted as being integral with waveguide (112), in alternativeembodiments the blade (124) is of separate structure and attached to thedistal end of waveguide (112), such as by threaded attachment.Ultrasonic surgical device (110) also includes a hollow cylindricalsheath (160) in which at least a portion of waveguide (112) andoptionally a portion of blade (124) is positioned.

As in the previous embodiment, although at least a portion of thewaveguide (112) is located within the sheath (160), the sheath (160) isnot secured directly to the waveguide (12). Instead, and as detailedbelow, waveguide (112) is operatively attached at its proximal end to atransducer (182), and the proximal end of sheath (160) is secured withinthe handpiece (172).

Ultrasonic surgical device (110) further includes an ultrasonictransducer (182) mounted to the handpiece (172), as shown. Transducer(182) may be removably mounted to the handpiece (172), such as bythreaded engagement therewith, or may be fixed within or on thehandpiece (172). Transducer (182) includes a housing (184) which isconfigured to facilitate grasping and manipulation of the surgicaldevice (110) along with stationary handle (174) of handpiece (172). Theproximal end of the transducer housing (184) includes an electricalconnector (e.g., a plug or a socket) for operative connection to agenerator. Thus, an electrical drive signal comprising an alternatingcurrent of ultrasonic frequency will be supplied from the generator tothe transducer (182) via a cable operatively connected to the electricalconnector on the transducer housing. As with the previous embodiment,transducer (182) converts the drive signal into a standing, ultrasonicvibrational wave in the transducer, including the transducer horn (orvelocity transformer) (185).

Although not shown in FIGS. 3A or 3B, a threaded mounting stud issecured to the distal end (186) of the transducer horn (185), such as bybeing threadably and adhesively secured within a threaded bore in thedistal end (186) of the transducer horn (185). Thus, as in the previousembodiment, this threaded stud extends distally away from the distal end(186) of transducer horn (185), and this distal end (186) of transducerhorn (185) is located at an antinode of the standing vibrational waveproduced by the transducer (182) (e.g., at 55 kHz). Similar to theprevious embodiment, the proximal end of waveguide (112) includes athreaded bore (not shown) that extends inwardly (i.e., distally) fromthe proximal end of the waveguide (112). This threaded bore is sized andconfigured to threadably receive the mounting stud on the distal end ofthe transducer horn (185), such that the waveguide (112) is operativelycoupled to the transducer (182) by threadably securing the waveguideonto the mounting stud of the transducer horn (185). When coupled inthis manner (i.e., as seen in FIG. 3B), the standing vibrational waveproduced in the transducer (182) is propagated along the length of thewaveguide (112).

The sheath (160) may be affixed to the handpiece (172) in a variety ofways known to those skilled in the art, such as by welding, adhesive,mechanical fasteners and/or swaging. In the exemplary embodiment shownin FIGS. 3A and 3B, the proximal end of sheath (160) and the waveguide(112) are secured within handpiece (172) by a mounting pin (191).

As seen in FIG. 3A, at least a portion of blade (124) extends beyond thedistal end wall (162) of sheath (160). Once again it will be understoodthat the waveguide (112), blade (124), sheath (160) and/or handpiece(172) can be configured such that more or less of the blade extendsbeyond the distal end of sheath (160) than depicted in FIG. 3A. In thisinstance, the entirety of the blade faces (i.e., the curved portion ofthe blade) extends beyond the distal end wall (162) of sheath (160). Aswith the previously described embodiment, one or more resilient rings(117) are provided on the exterior of waveguide (112) (e.g., siliconerings) and act as spacers that not only maintain the waveguide (112)centered with sheath (160), but also are located at vibrational nodes ofthe waveguide (112) in order to limit damping of the standing wave atthe drive frequency while also damping frequencies other than the drivefrequency.

Clamp member (150) includes a pad (151) mounted thereto for compressingtissue against a face or edge of the blade (124) in order to facilitatethe cutting and coagulating of tissue. Pad (151) is formed of apolymeric or other compliant material, and engages an edge or face ofthe blade (124) when the clamp member (150) is pivoted to its fullyclosed position shown in FIG. 17. Pad (151) can comprise, for example,PTFE or polyimide (PI), with or without added filler materials such asglass, metal and/or carbon. In some embodiments, pad (151) comprises ahigh temperature resistant material. Pad (151) is attached to the clampmember (150) by, for example, an adhesive or mechanical fastener. Asseen in FIGS. 3A and 3B, the exposed surface of the pad (151) provides acurved tissue-engaging surface. In the embodiment shown, thistissue-engaging surface has a curvature corresponding to the curvatureof the corresponding portion of the first face of the blade.

In addition, as best seen in FIG. 16, serrations (152) are formed in theclamping surface of pad (151) in order to enhance tissue grasping andmanipulation, even when the blade (124) is not vibrating, thus allowingthe surgical device (110) to be used as a conventional forceps when notbeing used for cutting/coagulating tissue. The serrations (152) areprovided in two rows, with a recessed region (152) therebetween.Recessed region (152) is shaped and configured for mating engagementwith an adjacent face of the blade (124), as best seen in FIG. 16. Byconforming the surface of recessed region (152) to that of the adjacentface of the blade (124), there are no gaps between the tissue pad (151)and the blade when the tissue pad is clamped against the adjacent faceof the blade, thus ensuring that tissue is cut completely along thelength of the blade. It will also be noted that the distal end of sheath(160) is tapered in order to limit tissue from entering the interior ofthe sheath (160) during use.

The proximal end of the clamp member (150) is pivotally mounted to thesheath (160), adjacent the distal end thereof, by a pivot pin (153). Theclamp member (150) is also pivotally attached to the distal end of anactuator rod (179) at pivot pin (154). Actuator rod (179) is mounted tothe handpiece (172) for linear movement parallel to the longitudinalaxis of waveguide (112), and extends outwardly from the handpiece (172)directly above the sheath (160). From the open position of FIG. 3A,linear movement of the actuator rod (179) in the distal direction (i.e.,towards blade (124)), causes the clamp arm to pivot towards its closedposition, such that pad (151) will eventually engage a face of the blade(124) (see FIG. 17). Similarly, from the closed position, linearmovement of the actuator rod (179) in the proximal direction (i.e.,towards transducer (182)), causes the clamp arm to pivot to its openposition of FIG. 3A.

In order to effect linear, longitudinal movement of actuator rod (179),a pivoting handle (175) is pivotally mounted to handpiece (172), asshown. Handle (175) is pivotally secured within handpiece (172) at pivotpin (176), and the distal end of handle (175) is pivotally attached tothe proximal end of actuator rod (179) at pivot pin (177) withinhandpiece (172). Thus pivotal movement of handle (175) away fromhandpiece (172) causes the clamp member (150) to pivot towards its openposition (FIG. 3A), while pivotal movement of handle (175) towardshandpiece (172) causes the clamp member (150) to pivot towards itsclosed, tissue clamping, position.

As mentioned previously, the blades depicted and described herein haveat least one curved surface along with a plurality of blade edgessuitable for ultrasonic cutting of tissue. These blades can befabricated from turned stock (e.g., round stock) using only end millsand no Z-axis milling, while still providing a plurality of blade edgessuitable for cutting tissue.

The curved blades depicted and described herein are provided at thedistal end of a waveguide, and have a curved portion that includes atleast five faces that extend lengthwise along at least a portion of thelength of the blade. Each of the faces of the blade is flat across itswidth, which width extends perpendicular to the projected longitudinalaxis (L) of the waveguide. Along their respective lengths (i.e., thedirection orthogonal to their respective widths), each of the bladefaces is either flat or includes one or more curved segments (with orwithout one or more flat segments), with each of the curved segments ofan individual face being curved in the same direction (however, thatcurvature can be positive and/or negative curvature). At least one ofthe faces of the blade includes at least one of said curved segments. Insome embodiments wherein the curved portion of the blade has an evennumber of faces (e.g., six), two opposing faces (i.e., faces on oppositesides of the blade) have at least one curved segment. The direction ofcurvature of the curved segments of an individual face does not changealong its length, with the curvature gradient on the surface of thecurved segments of each face being non-zero in one direction and zero inthe perpendicular direction (i.e., across their widths). Thus, the axesof curvature of each of the curved segments of an individual face areparallel to one another (as seen, for example, in FIG. 5). In addition,the axes of curvature of each of the curved segments of the faces of theblade is perpendicular to a plane which includes the longitudinal axis(L) of the waveguide (i.e., the faces of the blade include no curvedsegment having an axis of curvature which is not perpendicular to aplane which includes the longitudinal axis of the waveguide). Thus, theincluded angle between adjacent faces is also constant along the lengthof the curved portion of the blade.

Accordingly, each of the faces of the curved portion of the bladecomprises a developable surface, thereby facilitating the manufacture ofthe blade from turned stock (e.g., round stock) using an end mill andonly X- and Y-axis movement of the workpiece (i.e., the blade material,e.g., round stock) and mill with respect to one another. No Z-axismovement or cutting is required during milling, since each of the facesof blade is flat and/or includes one or more right cylindrical surfaces(circular or elliptic cylindrical surfaces) or other surface that iscurved in a single direction. It will be understood that the bladesdescribed herein can be fabricated from any turned stock, including notonly straight or tapered cylindrical stock but also straight or taperedelliptical turned stock. (The configuration of the blade faces describedby the foregoing may be better understood with references to the methodof producing the blade faces from round stock, as further describedherein.)

The intersection of each pair of adjacent faces of the curved portion ofthe blade defines a cutting edge, which extends along at least a portionof the length of the blade. Because each adjacent blade face is notnecessarily curved in the same manner, a variety of cutting edge shapesand configurations can be provided on the same blade in order to givemore cutting options to the medical practitioner.

In some embodiments, the five or more faces of the blade, and hence thefive or more cutting edges therebetween, extend to the distal tip (26)of the blade (e.g., FIG. 6). In other embodiments (e.g., FIG. 15), oneor more of the blade faces terminates in a cylindrical face (527) (orother turned surface). Cylindrical face (527) results when two adjacentfaces intersect along the length of the blade but adjacent their distalends that intersection extends outside the turned profile of the stockused to fabricate the blade. In the embodiments shown in FIG. 15,cylindrical face (527) comprises a portion of the cylindrical stock fromwhich blade (524) has been fabricated. It will be understood, however,that the blade described herein can be fabricated from any turned stock,including not only cylindrical stock but also, for example, ellipticalturned stock.

In some embodiments, the curved portion of the blade has six facesarranged as three pairs of opposing faces, such that the cross-sectionalshape of the blade in any plane perpendicular to the longitudinal axisof the waveguide through the curved portion of the blade (except throughsome transition segments, as described below) is a hexagon. The includedangle between adjacent faces in these embodiments is constant along thelength of the curved portion of the blade, and each is between about 100and about 140 degrees. In one particular embodiment, all of the includedangles between adjacent faces of a blade having a curved portion withsix faces are about 120 degrees (e.g., blade 424 in FIG. 14).

The proximal end of the blade in some embodiments includes a cylindricalsection between the distal end of the waveguide and the plurality offaces of the blade. Blade (24), for example, includes cylindricalportion (25) located between the taper (18C) adjacent the most-distalnode of the waveguide (12) and the proximal ends of blade faces (28, 30,32, 34, 36, 38) (see FIGS. 1 and 4A). In other embodiments, particularlywhen a taper is not provided at the distal-most node, the blade includesa cylindrical portion located between the distal-most node of thewaveguide and the plurality of faces (i.e., when there is no taperbetween the distal-most node and the blade). In addition, in stillfurther embodiments, no such cylindrical portion is included on theproximal end of the blade.

FIGS. 4A-4E depict various views of blade (24) which, in thisembodiment, includes a curved portion having six faces (28-38) extendingdistally away from cylindrical portion (25) to distal tip (26). In thisparticular embodiment, each face (28-38) includes a curved transitionsegment (A), a flat middle segment (B) and a curved distal segment (C).Transition segments (A) of each face provide a smooth transition fromcylindrical portion (25) to the middle and distal segments (B, C) of thecurved portion of the blade, and gradually increase in width in thedistal direction (i.e., towards distal tip (26)). Not only are thetransition segments (A) necessitated by the use of an end mill to formthe blade faces in turned stock, the transition segments (A) help toreduce stress at the intersection of the faces and the cylindricalportion (25). Nevertheless, the transition segments (A) as well as theedge between a transition segment (A) and the adjacent face (e.g., anadjacent transition segment) are also usable portions of the blade.Thus, each of these transition segment edges can be used for cuttingand/or cauterizing tissue.

Transition segment (A) of each of the blade faces is flat across itswidth and curves in a single direction along its length. In theembodiment shown in FIGS. 4 and 5, middle segment (B) of each of theblade faces, on the other hand, is flat across its width and also flatalong its length, extending at an angle to the longitudinal axis of thewaveguide such that the blade (24) is tapered along middle segments (B).In alternative embodiments, one or more of the middle segments (B)extend parallel to the longitudinal axis (L) of the waveguide. Finally,each distal segment (C) of each of the faces of blade (24) is flatacross its width and curved (in a single direction) along its length. Inalternative embodiments, one or more (but not all) of the distalsegments (C) are flat along their respective lengths.

As mentioned above, the curved portion of blade (24) has six faces(28-38) extending distally away from cylindrical portion (25) to distaltip (26). The faces of blade (24) are arranged as three pairs ofopposing faces, such that the cross-sectional shape of the blade in anyplane perpendicular to the longitudinal axis (L) of the waveguidethrough any point of middle segments (B) or distal segments (C) is ahexagon. The included angle between adjacent faces is constant along thelength of the blade, and each is between about 100 and about 140degrees. In the embodiment shown in FIG. 4, all of the included anglesbetween adjacent faces are about 120 degrees such that thecross-sectional shape of the blade in any plane perpendicular to thelongitudinal axis (L) of the waveguide through any point of middlesegment (B) or distal segment (C) is an equiangular hexagon.

It should be noted that an equiangular hexagon simply means that theincluded, i.e., interior, angles are identical, and opposing sides ofthe hexagon are parallel to one another. However, since the equiangularhexagonal cross-sectional shape described above is defined in a planeperpendicular to the longitudinal axis (L) of the waveguide and opposingfaces, although parallel across their widths and only curving in asingle direction, may have different amounts of curvature, opposingsides of this equiangular hexagon are not necessarily the same length.Thus, the blades described herein, although capable of beingmanufactured using only conventional end mills and no Z-axis milling,can have a plurality of curved cutting edges which are not necessarilycurved in a single direction (despite the fact that each individual faceis curved in only one direction).

Of course it will be understood that the included angle between adjacentfaces in alternative embodiments will depend, in part, on how many facesare provided on the blade. For example, in some embodiments of a bladehaving five faces, each of the included angles between adjacent faces isbetween about 88 and about 128 degrees, or, in some instances, each isabout 108 degrees such that the cross-sectional shape of the blade inany plane perpendicular to the longitudinal axis of the waveguidethrough the curved portion of the blade (except through some transitionsegments, where present) is an equiangular pentagon. Similarly, in someembodiments of a blade having seven faces, each of the included anglesis between about 108 and about 148 degrees, or, in some instances, eachis about 128 degrees such that the cross-sectional shape of the blade inany plane perpendicular to the longitudinal axis of the waveguidethrough the curved portion of the blade (except through some transitionsegments, where present) is an equiangular heptagon. And in someembodiments of a blade having eight faces, each of the included anglesis between about 115 and about 155 degrees, or, in some instances, eachis about 135 degrees such that the cross-sectional shape of the blade inany plane perpendicular to the longitudinal axis of the waveguidethrough the curved portion of the blade (except through some transitionsegments, where present) is an equiangular octagon.

In still further embodiments, the blade may be configured to have agreater variation in the included angles than those specified in theprevious paragraphs. Thus, at least one of the included angles betweenadjacent faces is more than 20 degrees, more than 30 degrees, or morethan 45 degrees less than at least one of the other included anglesalong at least a portion of the blade. For example, blade (624) shown inFIGS. 18 and 19 has five faces such that the cross-sectional shape ofthe blade in any plane perpendicular to the longitudinal axis of thewaveguide through the curved distal segments (C) of the blade (624) is apentagon. However, although four of the included angles between adjacentfaces is about 120 degrees, the fifth included angle (a) is about 60degrees. Thus, cutting edge (637) is sharper than the other four cuttingedges.

As also seen in FIGS. 4 and 5, since transition segments (A) of thefaces (28-38) do not all have the same length, the cross-sectional shapeof the blade in a plane perpendicular to the longitudinal axis (L) ofthe waveguide through some portions of transition segments (A) willinclude portions of a cylindrical surface (40) corresponding to that ofthe round stock from which the blade is fabricated (see, e.g., FIG. 12F,wherein 28A designates the transition segment of the first face (28) ofthe curved portion of the blade (24)). In some embodiments, transitionsegments A comprise less than half of the length of the curved portionof the blade, or even less than one third of the length of the curvedportion of the blade.

In the alternative embodiment depicted in FIGS. 18 and 19, while thecurved distal segments (C) comprise five faces, transition segments (A)include a sixth face (638A) in order to facilitate providing a reducedincluded angle (α) between two of the distal segment faces.Nevertheless, each face (628, 630, 632, 634, 636) includes a curvedtransition segment (A), a flat middle segment (B) and a curved distalsegment (C). As before, transition segments (A) of each face provide asmooth transition from cylindrical portion (625) to the middle anddistal segments (B, C) of the blade. Each transition segment (A) of eachof the blade faces, as well as transition face (638A), is flat acrossits width and curves in a single direction along its length. Middlesegment (B) of each of the blade faces, on the other hand, is flatacross its width and also flat along its length, extending parallel tothe longitudinal axis of the waveguide. Finally, distal segments (C) ofeach of the blade faces is flat across its width and curved (in a singledirection) along its length. Also, like blade (524) in FIG. 15, firstface (628) and, in part, second and fifth faces (630, 636), terminatesin a cylindrical face (627).

As best seen in FIGS. 4A, 4B and 5, first face (28) intersects secondface (30) along cutting edge (29), through transition segment (A),middle segment (B) and distal segment (C) of the blade (24). Similarly,second face (30) intersects third face (32) along cutting edge (31),third face (32) intersects fourth face (34) along cutting edge (33),fourth face (34) intersects fifth face (36) along cutting edge (35),fifth face (36) intersects sixth face (38) along cutting edge (37), andsixth face (38) intersects first face (28) along cutting edge (39). Ifdesired, the cutting edges can be polished to dull the edges or groundto sharpen the edges. Polishing of the entire blade can also beperformed in order to improve the surface finish, improve the life ofthe blade (prevent fatigue) and/or to adjust the speed of cutting. Withregard to the three pairs of opposing faces of blade (24), first face(28) is in opposing relation to fourth face (34), second face (30) is inopposing relation to fifth face (36), and third face (32) is in opposingrelation to sixth face (38). Since each included angle between adjacentfaces is constant along the length of the curved portion of blade (24),and is about 120 degrees, the axes of curvature for the curved segmentsof each opposing pair of faces are parallel to one another—i.e., eachpair of opposing faces only curves in the same direction (although thatdirection of curvature can be positive or negative). This is best seen,for example, in FIG. 5 which depicts a side plan view of blade (24) (andis the same view as FIG. 4B).

As shown in FIG. 5, transition segments (28A, 34A) of the opposing firstand fourth faces (28, 34) are curved along their lengths, middlesegments (28B, 34B) are flat (along their lengths and widths), anddistal segments (28C, 34C) are curved along their lengths. Each of thesesegments (28A-C, 34A-C) is flat across its width, wherein the widthextends perpendicular to the longitudinal axis (L) of the waveguide (12)(i.e., perpendicular to the plane of FIG. 5). Curved segments (28A, 28C,34A, 34C) are all curved in the same direction, such that their axes ofcurvature (D′, E′, F′, G′) are parallel to each other and areperpendicular to a plane which includes the longitudinal axis (L) of thewaveguide (i.e., perpendicular to the plane of FIG. 5). Of course, whilethe curved segments (28A, 28C, 34A, 34C) are all curved in the samedirection, distal segment (34C) of fourth face (34) is negatively curved(negative radius of curvature (F)) while the other curved segments (28A,28C, 34A) are positively curved (positive radii of curvature (D, E, F)).As used herein, a concave surface has a positive radius of curvature,while a convex surface such as distal segment (34C) of fourth face (34)has a negative radius of curvature.

In some embodiments of the blades described herein, the transitionsegments of each face are concave (e.g., 28A and 34A in FIG. 5). Thus,the transition segments effectively provide a taper that reduces thecross-sectional size of the blade. Also, in some embodiments of theblades described herein (e.g., blades (24, 124, 224)), when one of themiddle or distal segments of each pair of opposing faces is concave(e.g., 28C in FIG. 5), the corresponding middle or distal segment of theopposing face is convex (e.g., 34C in FIG. 5). In addition, in theseembodiments the radius of curvature of the concave middle or distalsegment of a blade face is equal to or greater than the correspondingmiddle or distal segment of the opposing face. For example, in theembodiment shown in FIG. 5, the radius of curvature (E) of concavedistal segment (28C) of first face (28) is greater than the radius ofcurvature (G) of convex distal segment (34C) of fourth face (34). Inthis manner, the cross-sectional area of the curved portion of the bladein these embodiments will not increase along any portion of its length.Rather, the cross-sectional area of the curved portion of the blade willdecrease between its proximal and distal ends such that the blade istapered along its length and the blade is its narrowest at distal tip(26).

Although each of the six faces (28-38) of blade (24) includes a singlemiddle segment (28B-38B), any number of middle segments of varyingcurvature (or no curvature) may be provided between transition segments(28A-38A) and distal segments (28C-38C). In the embodiment shown in FIG.5, although the middle segments of all of the faces (28-38) are notcurved (i.e., have a zero curvature gradient), they are tapered suchthat the distance between opposing middle segments decreases in thedistal direction.

It will be understood that any number of flat and curved segments may beprovided on any of the plurality of faces of the curved portion of theblade. For example, in some embodiments, each face has at least onesegment that is curved, such as each face having a curved distalsegment, with or without distinct transition and middle segments, eachof which (transition and middle segments) may be straight or curvedalong their length. In other embodiments the entirety of one or morefaces is curved, with a single radius of curvature for the entire lengthof the face (e.g., first face (228) of blade (224) in FIG. 6).

FIGS. 6A-6E depict an alternative embodiment of a blade (224) having sixfaces (228-238) extending distally away from cylindrical portion (225)to distal tip (226). In this particular embodiment, each face (228-238)includes a transition segment (A) and a distal segment (C) (there is noflat middle segment on any of the six faces). Transition segments (A) ofeach face provide the transition from cylindrical portion (225) to thedistal segments (C) of the blade. Like the previous embodiment, sincetransition segments (228A-238A) provide a taper which reduces thecross-sectional area of the blade from cylindrical portion (225) to theremainder of the curved portion of the blade, transition segments(228A-238A) gradually increase in width in the distal direction (i.e.,towards distal tip (226)). Unlike blade (24), the distal end oftransition segments (228A-238A) are located at varying distances fromthe distal end of the waveguide (212). Once again, transition segment(A) of each of the blade faces is flat across its width and curves in asingle direction along its length, with each transition segment(228A-238A) being concave. Similarly, distal segment (C) of each of theblade faces is flat across its width and curved (in a single direction)along its length. In this embodiment, however, each distal segment ofthe blade faces comprises a complex curve of continuously changingradius, however, that curvature is nevertheless in a single directionalong the length of the distal segment (e.g., as depicted schematicallyin FIG. 20).

As before, the six faces (228-238) of blade (224) are arranged as threepairs of opposing faces, such that the cross-sectional shape of theblade in any plane perpendicular to the longitudinal axis (L) of thewaveguide through any point of distal segment (C) is a hexagon. Theincluded angle between adjacent faces is constant along the length ofthe blade, and each is about 120 degrees such that the cross-sectionalshape of the blade in any plane perpendicular to the longitudinal axis(L) of the waveguide through any point of distal segment (C) is anequiangular hexagon.

First face (228) intersects second face (230) along cutting edge (229),second face (230) intersects third face (232) along cutting edge (231),third face (232) intersects fourth face (234) along cutting edge (233),fourth face (234) intersects fifth face (236) along cutting edge (235),fifth face (236) intersects sixth face (238) along cutting edge (237),and sixth face (238) intersects first face (228) along cutting edge(239). With regard to the three pairs of opposing faces of blade (224),first face (228) is in opposing relation to fourth face (234), secondface (230) is in opposing relation to fifth face (236), and third face(232) is in opposing relation to sixth face (238). Since each includedangle between adjacent faces is constant the length of the blade (224),and about 120 degrees, the axes of curvature for the curved portions ofeach opposing pair of faces are parallel to one another—i.e., each pairof opposing faces only curve in the same direction (although thatdirection of curvature can be positive or negative, as in the previousembodiment). As with blade (24), when one distal segment (C) of a face(228-238) is concave, the distal segment (C) of the opposing face isconvex (e.g., the distal segment of first face (228) is concave, and thedistal segment of the opposing fourth face (234) is convex).

FIG. 7 depicts yet another alternative embodiment of a blade (324)having six faces (328-338) which intersect one another at includedangles of about 120 degrees. Once again each face includes a transitionsegment (A), a middle segment (B) and a distal segment (C). As before,transition segments (328A, 330A, 332A, 334A, 336A, 338A) are flat acrosstheir respective widths and curve (concavely) in a single directionalong their respective lengths. In this embodiment, however, the middleand distal segments (B, C) of opposing second and fifth faces (330, 336)are flat along their entire lengths. Faces (328, 332, 334, 338) are flatalong their respective lengths at middle segments (B), but are curved ina single direction along their respective lengths at distal segments(C). Also in this embodiment, each pair of opposing faces that arecurved along their distal segments (C) have the same radius of curvaturesuch that the cross-sectional shape of the blade (324) in any planeperpendicular to the longitudinal axis (L) of the waveguide through anypoint of middle segment (B) or distal segment (C) is an equiangular,semi-regular hexagon (opposing sides of the hexagon are congruent, i.e.,of equal length). Thus, the cross-sectional size of blade (324) does nottaper apart from transition segment (A). In addition, the axis of middlesegment (B) is parallel to the longitudinal axis of the waveguide.

FIGS. 8-12 depict a method of manufacturing blade (24) from a segment(42) of round stock, wherein the taper (18C) at the distal end of thewaveguide (12) has been omitted from FIGS. 8-12 for purposes of clarity.The waveguide (12) and blade (24) are machined from a single roundstock, and the omitted features of waveguide (12) (e.g., tapers (18))may be formed by methods known to those skilled in the art. Inparticular, the diameter of segment (42) of round stock (shown in FIG.8) has been reduced in FIG. 9 to provide not only the desired diameterof third segment (12C) of the waveguide (12), but also an annularsupport (20) for resilient ring (17B) which can be, for example, insertmolded over the support (20) or applied over the support (20) in otherways known to those skilled in the art. Support (20) and distal cylinder(42A) can be formed, for example, by turning the round stock on a latheto reduce its diameter, leaving distal cylinder (42A) at the end of theround stock having the same diameter as (or less than) the diameter ofthe original segment (42) of round stock. Distal cylinder (42A)corresponds to middle and distal segments (B, C) of the final blade(24). Alternatively, the blade faces can be milled into the fulldiameter round stock.

Following size reduction of the round stock to the configuration shownin FIG. 9, the six faces of the blade (24) are machined using one ormore end mills to produce the configuration shown in FIG. 10. However,no Z-axis milling is required, and all six faces can be milled usingjust three orientations of the round stock. For example, first andfourth faces (28, 34) are milled into the round stock using an end mill(44) as shown in FIGS. 10 and 13. The workpiece (the round stock,optionally reduced in size as shown in FIGS. 9) is positioned on the X-Ytable of a milling machine, as shown in FIGS. 13A and 13B. The workpieceis then advanced in the X- and Y-directions, without rotation of theworkpiece, as the end mill is spinning (about a Z-oriented axis). As aresult, first face (28) is milled into the workpiece, wherein first face(28) is flat across its width (i.e., the Z-direction in FIG. 13B).Fourth face (34) is milled in the same manner, without the need torotate the workpiece about its longitudinal axis (L) but rather merelymoving the workpiece in the Y-direction for reorientation prior tomilling fourth face (34). (Alternatively, the workpiece may be rotated180 degrees about its longitudinal axis from the position shown in FIG.13A in order to machine (mill) fourth face (34).)

Next, the workpiece is rotated (clockwise, when viewed from the distalend) about its longitudinal axis (L) 60 degrees, and third and sixthfaces (32, 38) are milled using one or more end mills in the same manner(i.e., only X- and Y-movement of the workpiece with respect to the endmill which is spinning about the Z-axis) (see FIG. 11). Finally, theworkpiece is rotated about its longitudinal axis (L) another 60 degrees,and second and fifth faces (30, 36) are milled using one or more endmills in the same manner as before (i.e., only X- and Y-movement of theworkpiece with respect to the spinning end mill) (see FIG. 12). It willbe understood, of course, that the order of cutting the pairs ofopposing faces may be changed. Similarly, opposing faces can be milledby moving the spinning end mill in the X- and Y-directions with respectto a stationary workpiece, or even a combination of these techniques byeffecting X- and Y-movement of the workpiece with respect to a spinningend mill (i.e., by X- and Y-direction movement of both the workpiece andthe spinning end mill).

FIG. 14 depicts yet another alternative embodiment of a blade (424)having six faces which intersect at an included angle of about 120degrees. Like the previous embodiments, each face is flat across itswidth and curved in a single direction along its length. In thisembodiment, however, first face (428), second face (430) and the sixthface located adjacent first face (428) (not visible in FIG. 14) arecontinuously curved along their entire lengths, having a positive,elliptical curvature (i.e., concavely curved). As also used herein, aconcave surface has a positive curvature, while a convex surface has anegative radius of curvature. As also used herein, the axis of curvatureof an elliptically curved surface, such as first face (428) whosecurvature is defined by an ellipse (D) in FIG. 14, is defined as a lineextending through the center point of the ellipse parallel to the widthof the blade face and perpendicular to the longitudinal axis (L). Theaxis of rotation of other complex curves can be similarly defined.

As shown in FIG. 14, along its length, the curvature of first face (428)follows a portion of an ellipse (D) that is tilted with respect to thelongitudinal axis (L) of the waveguide. Thus, as seen in FIG. 14, themajor axis (E) of ellipse (D) is not parallel to the longitudinal axis(L), but rather is tilted at an included angle of about 5 degrees. Ofcourse the elliptical path of first face (48) need not be tilted withrespect to the longitudinal axis (L) or may be tilted to varying degrees(e.g., up to about 20 degrees, or between about 2 and about 10 degrees).Since first face (428) is continuously curved along the elliptical pathits entire length, first face (428) does not include a separate anddistinct transition segment. Instead, the concave transition segment isincorporated into the continuously curved first face (428). Second face(430) and the sixth face of the blade (424) are similarly ellipticallycurved, although not necessarily following elliptical curves identicalto ellipse (D) (e.g., can be tilted or non-tilted, have differenteccentricities and/or different radii). Thus, the second and sixth facesof blade (424) also do not have separate and distinct transitionsegments.

The distal segments (C) of the opposing faces (i.e., third face (432) inopposed relationship to the sixth face, fourth face (434) in opposedrelationship to first face (428), and the fifth face in opposedrelationship to second face (430)) are also elliptically curved in asimilar manner, and thus comprise convexly curved elliptical surfaces.These opposing faces also have transition segments (A) (e.g., transitionsegment (432A) of third face (432)) which are concavely ellipticallycurved, as discussed previously herein. In this particular embodiment,the opposing convexly curved distal segments follow portions of tiltedellipses similar to their opposing concave faces. Thus, each pair ofopposing faces are curved along their lengths in the same, singulardirection, with one face of each pair concavely curved along its entirelength, and the other, opposing face of each pair having a convexlycurved distal segment and a concavely curved transition segment.

In addition, blade (424) is also symmetrical with respect to a planethat includes the longitudinal axis (L) of the waveguide (i.e., a planeparallel to the plane of FIG. 14 that includes longitudinal axis (L).Because of this as well as the curvature of the blade, the blade willvibrate both longitudinally and transversely (i.e., in the X- andY-directions of FIG. 13A, but not in the Z-direction).

It will be understood, of course, that the faces of blade (424) can becurved in any of a variety of manners, such as having a single, uniformradius of curvature (i.e., a surface that follows a portion of acircular path), a constantly varying radius of curvature along itsentire length (or a portion thereof), or segments of varying curvedshapes and/or curvature including one more segments that are flat acrossboth their width and length. However, the direction of curvature of eachof the six faces does not change along their respective lengths, and theaxes of curvature of each of pair of opposing faces (e.g., first face(428) and fourth face (434)) are parallel to one another and areperpendicular to a plane that includes the longitudinal axis (L) of thewaveguide. In addition, the cross-sectional shape of blade (424) throughany portion of the blade distal to the transition segments is anequiangular hexagon.

It will also be noted from FIG. 14 that, although cylindrical portion(425) extends distally away from the most-distal taper (418C) of thewaveguide (located at the most-distal node of the waveguide), a distallyincreasing taper (427) is also provided between cylindrical portion(425) and the transition segments (A) of the blade faces.

FIG. 15 depicts yet another alternative embodiment of a blade (524)having six faces (528-538) which intersect at an included angle of about120 degrees. Here, because the radius of curvature of distal segment(528C) of first face (528) is sufficiently small (i.e., more curvature),first face (528) ends before the distal end of the workpiece from whichit has been fabricated. As a result, first face (528) and, in part,second and sixth faces (530, 538), terminates in cylindrical face (527),which is a remnant of the distal cylinder (e.g., 42A in FIG. 9) createdby lathe turning of the original round stock. Thus, in the embodimentshown in FIG. 15, while the curved portion of the blade (524) once againhas six faces arranged as three pairs of opposing faces, thecross-sectional shape of the blade in any plane perpendicular to thelongitudinal axis of the waveguide through the curved portion of theblade is a hexagon except through the proximal-most portions of thetransition segments and except through the cylindrical face (527).

FIGS. 21-25 depict another alternative embodiment of a blade (824)having six faces (828-838) which intersect at an included angle of about120 degrees. These faces extend distally away from cylindrical portion(825) to distal tip (826). Like the previous embodiments, each face isflat across its width and curved in a single direction along its length.The six faces are arranged in three pairs, such that the cross-sectionalshape of the blade in any plane perpendicular to the longitudinal axisof the waveguide through the curved portion of the blade (except throughsome transition segments, as described herein) is a hexagon. Inaddition, the opposing faces of each pair are parallel across theirwidths, and curve in the same direction. However, one face of a pair hasa positive curvature (a concave surface) while the other face has anegative curvature (a convex surface). In addition, all of the axes ofcurvature of the six blade faces are perpendicular to a plane thatincludes the longitudinal axis (L) of the waveguide. Given the hexagonalcross-section of the blade, however, there are three such planes (onefor each pair of opposed faces). Thus, the included angle betweenadjacent faces is a constant 120 degrees along the length of the curvedportion of the blade. The intersection of each pair of adjacent faces ofthe curved portion of the blade defines a cutting edge for use duringsurgical procedures.

All six blade faces of blade (824) have an elliptical curvature, withthe ellipses defining the curvature tilted. For the convexly curvedfaces, a concavely curved transition segment is once again included inorder to provide a smooth transition from the cylindrical stock. Thecurvature of each of these transition segments follows a portion of acircle, as seen in FIGS. 21 and 23. For the three adjacent, concavelycurved faces (828, 830, 838), a separate and distinct transition segmentis not included, as the concave transitions from the cylindrical portion(825) are incorporated into the concavely curved face.

With reference to FIGS. 21-25, wherein each successive view is rotatedcounterclockwise (as viewed from the distal end of the blade), three ofthe faces (832, 834, 836) include a concavely curved transition segment(832A, 834A, 836A), and an elliptically curved distal portion of theface. These transition segments provide a smooth transition from thecylindrical portion to the convexly curved faces (832, 834, 836). Theconcavely curved faces (828, 830, 838) have no transition segments. Asbefore, each of the transition segments of the curved blade faces isflat across its width and curves in a single direction along its length.Likewise, each distal segment of the blade faces is flat across itswidth and curved (in a single direction) along its length.

In the embodiment of FIGS. 21-25, first face (828), second face (830)and sixth face (838) are continuously curved along their entire lengths,having a positive, elliptical curvature (i.e., concavely curved). Thus,the first, second and sixth faces of blade (824) do not have separateand distinct transition segments. As shown in FIG. 21, along its length,the curvature of first face (828) follows a portion of an ellipse (D8A)that is tilted with respect to the longitudinal axis of the waveguide.Thus, as seen in FIG. 21, the major axis (E8A) of ellipse (D8A) is notparallel to the longitudinal axis (L9), but rather is tilted at anincluded angle of about 5 degrees. Of course the elliptical path offirst face (848) need not be tilted with respect to the longitudinalaxis (L8) or may be tilted to varying degrees (e.g., up to about 20degrees, or between about 2 and about 10 degrees). Since first face(828) is continuously curved along this elliptical path for its entirelength, first face (828) does not include a separate and distincttransition segment.

Second face (830) and sixth face (838) of the blade (824) are similarlyelliptically curved, although not necessarily following ellipticalcurves identical to ellipse (D8A) (e.g., can be tilted or non-tilted,have different eccentricities and/or different radii). In the particularembodiment shown, the curvature of second face (830) follows a portionof an ellipse (D8C) that has a somewhat greater eccentricity thanellipse D8A. Ellipse (D8C) is once again tilted with respect to thelongitudinal axis of the waveguide, as seen in FIG. 22. In thisinstance, the major axis (E8C) of ellipse (D8C) is tilted at an includedangle of about 2.5 degrees with respect to the longitudinal axis of thewaveguide. Once again the elliptical path of second face (830) need notbe tilted with may be tilted to varying degrees (e.g., up to about 20degrees, or between about 2 and about 10 degrees). Although theelliptical path of curvature of sixth face (838) is not shown in FIG.25, the curvature of sixth face (838) follows a portion of a tiltedellipse that is similar to ellipse (D8C) shown in FIG. 22 (e.g., tiltedat about 2.5 degrees, or alternatively up to about 20 degrees, orbetween about 2 and about 10 degrees).

The convexly curved distal portions (or segments) of the opposing faces(i.e., third face (832) in opposed relationship to the sixth face (838),fourth face (834) in opposed relationship to first face (828), and thefifth face (836) in opposed relationship to second face (830)) are alsoelliptically curved in a similar manner. These opposing faces also havetransition segments (A) (e.g., transition segment (832A) of third face(832)) which are concavely curved, as discussed previously herein. Inthis particular embodiment, transition segments (832A, 834Am 836A) areflat across their widths and curve in a single direction along thelength of that face. In the embodiment shown, the curvature of thesetransition segments (832A, 834A, 836A) follow a portion of a circle (G8)(see FIGS. 21 and 22). Once again, however, the axis of curvature of thetransition segments (i.e., the center of circle (G8)) is parallel to theaxis of curvature of the associated face, and is perpendicular to aplane that includes the longitudinal axis (L) of the waveguide. Thetransition segments may be curved along a portion of a similar circle(G8), or different sized circles can be used for one or more of thetransition segments.

The opposing convexly curved distal segments of third face (832) (inopposed relationship to the sixth face (838)), fourth face (834) (inopposed relationship to first face (828)), and the fifth face (836) (inopposed relationship to second face (830)) follow portions of tiltedellipses similar to their opposing concave faces. Thus, each pair ofopposing faces are curved along their lengths in the same, singulardirection, with one face of each pair concavely curved along its entirelength, and the other, opposing face of each pair having a convexlycurved distal segment and a concavely curved transition segment.

In the specific embodiment shown, the elliptical curvature of the distalsegment of fourth face (834) is not only negative (i.e., is convex), itfollows a portion of an ellipse (D8B) that, like ellipse (D8A), istilted with respect to the longitudinal axis (L) of the waveguide. Infact, although merely exemplary of one embodiment, ellipses D8A and D8Bare concentric (i.e., have a common center point and major and minoraxes) and have the same eccentricity. As a result, the distance betweenthe elliptically curved portions of the first and fourth faces (828,834) is constant along the length of the blade.

The elliptical curvature of the distal segment of fifth face (836) isalso negative (i.e., is convex), following a portion of an ellipse (D8D)that is not only tilted to the same extent as ellipse (D8C), is alsoconcentric with D8C (i.e., ellipses D8C and D8D have a common centerpoint and major and minor axes). However, the eccentricity of ellipse(D8D) is less than that of ellipse (D8C). As a result, second face (830)has slightly less curvature than fifth face (836) (i.e., is somewhatflatter), and therefore the distance between second face (830) and fifthface (836) decreases along their lengths such that the blade (824) isslightly tapered. Although the elliptical path of curvature of thirdface (832) is not shown in FIG. 25, the curvature of third face (832)follows a portion of a tilted ellipse that is similar to ellipse (D8D)shown in FIG. 22 (e.g., tilted at about 2.5 degrees, or alternatively upto about 20 degrees, or between about 2 and about 10 degrees). Thus, thedistance between third face (832) and sixth face (838) similarlydecreases along their lengths, provided additional tapering of the blade(824) along its length.

In addition, blade (824) is also symmetrical with respect to a planethat includes the longitudinal axis (L) of the waveguide (i.e., a planeparallel to the plane of FIG. 21 that includes longitudinal axis (L).Because of this as well as the curvature of the blade, the blade willvibrate both longitudinally and transversely (i.e., in the X- andY-directions of FIG. 13A, but not in the Z-direction).

It will be understood, of course, that the faces of blade (824) can becurved in any of a variety of manners, such as having a single, uniformradius of curvature (i.e., a surface that follows a portion of acircular path), a constantly varying radius of curvature along itsentire length (or a portion thereof), or segments of varying curvedshapes and/or curvature including one more segments that are flat acrossboth their width and length. However, the direction of curvature of eachof the six faces does not change along their respective lengths, and theaxes of curvature of each of pair of opposing faces (e.g., first face(828) and fourth face (834)) are parallel to one another and areperpendicular to a plane that includes the longitudinal axis (L) of thewaveguide. In addition, the cross-sectional shape of blade (824) throughany portion of the blade distal to the transition segments is anequiangular hexagon.

While various embodiments of ultrasonic surgical devices and bladesthereof have been described in detail above, it will be understood thatthe components, features and configurations, as well as the methods ofmanufacturing the devices and methods described herein are not limitedto the specific embodiments described herein.

1-47. (canceled)
 48. A blade for an ultrasonic surgical instrument, saidblade having a length, a distal end, and a curved portion comprising sixfaces extending lengthwise along at least portion of the length of theblade, each of said faces having a width, a length that extendsorthogonal to the width of the face, and a distal segment that extendsto the distal end of the blade, wherein: each of the faces is flatacross its width and, along its entire length, it flat or curved alongone or more curved segments, with each of the curved segments of anindividual face being curved in the same direction such that the axes ofcurvature of each of the curved segments of an individual face areparallel to one another and no face curves in more than one direction;the faces are arranged as three pairs of opposing faces such that theopposing faces of each pair are parallel across their widths, and theaxes of curvature of each of the curved segments of the opposing facesof each pair are parallel to one another; and at least one of saiddistal segments has a convex curvature along its length and the distalsegment of the face opposing said at least one convex distal segment hasa concave curvature along its length.
 49. The blade of claim 48, whereineach of said distal segments is curved such that the distal segment ofone face of each of said pairs has a convex curvature and the distalsegment of the other face of that pair has a concave curvature.